diff options
| author | Denys Vlasenko <dvlasenk@redhat.com> | 2015-04-10 16:06:58 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-04-11 14:08:53 +0300 |
| commit | 32caa06091cc59651222cdc971dc21eaab36b097 (patch) | |
| tree | fc3482c4f3c36384f87cef02c3748aaa42f6dce6 /arch/x86/kernel/perf_regs.c | |
| parent | 5df71b396b2d1fdd9d9f5a33e2eda5dc27c5632d (diff) | |
| download | linux-32caa06091cc59651222cdc971dc21eaab36b097.tar.xz | |
perf/x86/64: Simplify regs_user->abi setting code in get_regs_user()
user_64bit_mode(regs) basically checks regs->cs to point to a
64-bit segment. This check used to be unreliable here because
regs->cs was not always correct in syscalls.
Now regs->cs is always correct: in syscalls, in interrupts, in
exceptions. No need to emply heuristics here.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1428671219-29341-3-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/perf_regs.c')
| -rw-r--r-- | arch/x86/kernel/perf_regs.c | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c index a8d4e4862ace..8157d3900bc2 100644 --- a/arch/x86/kernel/perf_regs.c +++ b/arch/x86/kernel/perf_regs.c @@ -166,22 +166,8 @@ void perf_get_regs_user(struct perf_regs *regs_user, * be careful not to look at any other percpu variables that might * change during context switches. */ - if (IS_ENABLED(CONFIG_IA32_EMULATION) && - task_thread_info(current)->status & TS_COMPAT) { - /* Easy case: we're in a compat syscall. */ - regs_user->abi = PERF_SAMPLE_REGS_ABI_32; - } else if (user_regs->orig_ax != -1) { - /* - * We're probably in a 64-bit syscall. - * Warning: this code is severely racy. At least it's better - * than just blindly copying user_regs. - */ - regs_user->abi = PERF_SAMPLE_REGS_ABI_64; - } else { - /* We're probably in an interrupt or exception. */ - regs_user->abi = user_64bit_mode(user_regs) ? - PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32; - } + regs_user->abi = user_64bit_mode(user_regs) ? + PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32; regs_user->regs = regs_user_copy; } |